The invention relates to a process for polymerizing olefin(s). Generally, the invention relates to polymerization catalyst compositions, and to methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component slurry with a catalyst component solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention also relates to methods of preparing the catalyst component slurries, the catalyst component solutions, and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.
Advances in polymerization and catalysis have resulted in the capability to produce many new polymers having improved physical and chemical properties useful in a wide variety of superior products and applications. With the development of new catalysts the choice of polymerization (solution, slurry, high pressure or gas phase) for producing a particular polymer has been greatly expanded. Also, advances in polymerization technology have provided more efficient, highly productive and economically enhanced processes. Especially illustrative of these advances is the development of technology utilizing bulky ligand metallocene catalyst systems and other advanced metallocene-type catalyst systems.
To utilize these systems in industrial slurry or gas phases processes, it is useful that the catalyst compound be immobilized on a carrier or support such as, for example silica or alumina. The use of supported or heterogeneous catalysts increases process efficiencies by assuring that the forming polymeric particles achieve a shape and density that improves reactor operability and ease of handling. However, bulky ligand metallocene and metallocene-type catalysts typically exhibit lower activity when supported than when utilized in unsupported or homogeneous form. This xe2x80x9csupport effectxe2x80x9d makes commercialization of these promising catalyst systems more difficult.
U.S. Pat. Nos. 5,317,036 and 5,693,727 and European publication EP-A-0 593 083 and PCT publication WO 97/46599 all describe various processes and techniques for introducing liquid unsupported catalysts to a polymerization reactor.
U.S. Pat. No. 6,069,213 discloses combining a supported and an unsupported metallocene catalysts in the polymerization of olefins, European publication EP 0 965 601A disclose a combination of a solid Ziegler-Natta catalyst with a liquid catalyst in toluene or Kaydol activated with methyl alumoxane or modified methyl alumoxane, and Chinese Published Patent Application No. 97116451.7 discloses combining an unsupported metallocene with a supported methylalumoxane. None of these references, however, discloses a catalyst composition prepared by continuously combining a catalyst component slurry with a catalyst component solution, then introducing the combination into an operating polymerization reactor.
While all these methods have been described in the art, there exists a need to reduce the support effect for bulky ligand metallocene and metallocene-type polymerization catalyst compositions, for an improved method for introducing catalyst compositions, and especially for introducing mixed catalyst compositions, into a polymerization reactors, and for methods to control the properties of polymer products utilizing such catalyst compositions.
The invention generally provides polymerization catalyst compositions and methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution, and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.
In one aspect, the invention provides a process to polymerize olefin(s) which includes the steps of continuously combining a catalyst component slurry with a catalyst component solution to form a catalyst composition and introducing the catalyst composition and one or more olefin(s) into an operating polymerization reactor.
In another aspect, the invention provides a process to control polymer properties which includes the steps of continuously combining a catalyst component slurry with a catalyst component solution to form a catalyst composition, introducing the catalyst composition into a polymerization reactor with one or more olefin(s) to form a polymer product, measuring a sample of the polymer product to obtain an initial product property and changing a process parameter to obtain a second product property.